What does it mean to sign or a cellphone for a younger person?

[firefox]

In order to get a cellphone I would need someone to sign for it for me, which I was hoping my boyfriend would do but he has no idea what it means for him. It would only be for 4 months until I am 19.
So what does it mean for him to sign for it for me, if I pay for the bill?
What is the worst that could happen to him in 4 months?
Is there any reason he shouldn't If I am going to pay for the bill? (I have a job and I would never do that to him)
Any information is helpful!

 

[noname1]

Maybe they need like parent concent that's weird I'd call the company

 

[ScRSC³]

That means you are 18 now right? In that case you could sign up yourself. The age limit is 18+ not 19+.