You will be asked for some information, such as your Social Security Number and the address of the school(s) you want the transcripts sent to, and there may be a small fee (under $20). There’s a good chance you will be able to complete the entire request online using an electronic signature, but some schools will ask that you contact the registrar’s office and provide a paper request and signature.
If your transferred credits are coming from another regionally accredited university, most colleges will accept them. General education credits (English, math, history) tend to be the most transferable, but most other courses will transfer as well, even if only as elective credits.
Each school will have its own credit transfer policy.
Here’s an example of Stanford University’s transfer credit policies found on the registrar’s office page: