My fiancé will be coming back to the US hopefully this summer. I want her to continue here college education and she wants to have a part time job to keep her busy while she makes new friends/ gets settled in the US. Will she be able to go to school the next semester after she arrives? Are there any citizenship requirements etc. and work, how long until she can?

She should wait until she file adjustment of status, get approval, get SSN and driver's license. She will become LPR... can work and go to school, etc.

She has a SSN but doesn't know how to drive therefore won't have a license for a while what is LPR?

Lawful Permanent Resident... legal term of green card holder.