b1 or b2 visas

[2unik4u]

Hello every
I am US citizen and I want to request a visitor visa for my sons, one is 8 and the other one just turned 18. what is required to do this type of process?
I don't want to file the I-30 app. for residency, I just want them to visit.

[jnk]

You need to apply B2 visa for them.