Starfield

You will receive 4 companions from completing main missions
-Sarah Morgan, Sam Coe, Barrett, Andreja

There are 3 you can recruit during main missions
-Vasco - Beginning of the game when you receive your first ship just don't decline Vascos help
-Supervisor Lin & Heller - Both during main mission "Back to Vectera" they will have optional tasks to recruit.

The rest can be found at bars in main cities. They will cost around 12,000 - 18,000 credits.
New Atlantis - The Viewport
-Gideon Aker
-Maika Boros
-Simeon Bankowski
-Rafael Aguerro (If you saved him during main mission "Entangled")

Akila City - Hitching Post
-Omari Hassan
-Rosie Tannehill

Akila City - Aggies Bar
-Lyle Brewer
-Ezekiel

Neon
-Mickey Caviar (The Astral Lounge)
-Dani Garcia (Euphorika)

Cydonia - Broken Spear
-Moara Otero (Appears after main mission "The Old Neighborhood" is free to recruit)
-Andromeda Kepler

If you selected the Hero Worshipped trait you can also recruit the adoring fan who appears.

You do not need to actually assign the companion anywhere if your ship & outposts are full for the achievement to unlock. Just need 10.

There are over 20 companions available in the game, so you only need about half. Each of them are named characters, so generic specialists don't count. You don't need to assign them, so don't worry about your ship's crew capacity or your skills. Here's my suggestion for getting this the quickest, but requires a lot of creds to hire everyone. I would do quests in the city each appears in until you have enough to hire them, or start leveling your persuasion to cut their pay in half.

Select Hero Worshipped as a trait during character creation for an extra free companion,then do the main story until you meet Sarah and she joins you. Then immediately ask Vasco at the Lodge to join you, which is free. Then while in New Atlantis, you can hire Simeon, Gideon, and Marika at the Viewpoint bar at the spaceport. If you go directly there, the adoring fan from the trait will ask to join your crew as well, otherwise, he'll catch up to you eventually.

If Vasco counts and you took the trait, you're already at 6/10 before leaving New Atlantis! I then suggest traveling to Cydonia on Mars in the Sol system since it's close and your starting grav drive isn't the best. Once you enter the city, take the first right then, go left down some stairs to the Broken Spear Bar. You can hire Andromeda Kepler, who has the best name, and Moara there. Now we're at 7 or 8 after a single grav jump!

Last stop is Akila City on Akila in the Cheyenne system, which is still close enough to jump to with the starting ship. Head into the city until you pass through the wall, putting you in the middle of town. Slightly to the right is the Hitching Post, where you can hire Omari and Rosie. Hopefully, that pops the achievement, if not, head to the left side of town, down low against the wall, following signs for The Stretch. Along here, you can find Aggies Bar with a pool table. You can hire Lyle here and even get Ezekiel to join you for free if you answer his questions by making it seem like you enjoy travel. If you arrive in Akila City before the inevitable patch, you can loot a stores inventory from the puddle in front of Shepherds Goods, near the entrance to the city. You can take 5k creds from the box, and sell all the weapons and spacesuits elsewhere in town for another 10k credits, enough to hire almost anyone without persuasion! Then just use a seat or bed to wait 48 hrs, talk to talk to Shepard about trading, and everything will have reset within the puddle!

There you go, 12 crew easily accessed at the beginning of the game. It just may take time to make enough money to hire them all. Luckily, there's plenty of questing to do in all three of those locations, so you can both make money and level up your persuasion if you want.

There are loads of different crew members you can obtain, the below is how I obtained the 10 required for this achievement:
- Adoring Fan - Obtained the perk at the start of the game, they then run into you early on in the story.
- Andreja - Part of constellation, speak to her.
- Andomeda Kelper - Found in The Broken Spear on Cydonia, speak to her. Will cost credits.
- Barrett - Part of constellation, speak to him.
- Giden Aker - Found in The Viewport near the Spaceport in New Atlantis, speak to them. Will cost credits.
- Marika Boros - Found in The Viewport near the Spaceport in New Atlantis, speak to them. Will cost credits.
- Sam Coe - Part of constellation, speak to him.
- Sarah Morgan - Part of constellation, speak to her.
- Simeon Bankowski - Found in The Viewport near the Spaceport in New Atlantis, speak to them. Will cost credits.
- Vasco - Part of constellation, speak to him.

If you don’t find the companions I’ve mentioned above, sit in a chair wait a while and check the location again.
You DONT need to have them assigned for this achievement to count.

Hope my experience above, helps some of you out.

Hello, I will leave some tips that helped me, first, the only NPCs that count towards the achievement are the ones I will mention here (Don't waste your time and money for nothing recruiting generic NPCs):

Gideon Aker, Maika Boros, Simeon Bankowski, Rafael Aguerro, Hitching Post, Omari Hassan, Rosie Tannehill, Aggies Bar, Lyle Brewer, Ezekiel, Mickey Caviar, Dani Garcia, Broken Spear, Moara Otero, Andromeda Kepler

Second, every time you recruit, use the persuade option to pay half the amount, with this tip you taking 60 to 80k credits will be enough to complete the achievement requirements.

Third, if you are still reading this far, good morning, good afternoon and good night.