Ok ... the LLC is only a state designation and has nothing to do with a federal tax return UNLESS you choose to incorporate and before you do that you need to get educated on what your state requires and the fees that may be applied. If this "business" will not become a full time permanent situation then getting an LLC if one is not required and/or incorporating is like buying a big rig truck when a bicycle will do.
Seek local professional guidance and/or do some eductating on this matter yourself.
https://www.irsvideos.gov/Business/SBTW
https://www.irs.gov/businesses/small-businesses-self-employed/limited-liability-company-llc
https://www.irs.gov/businesses/small-businesses-self-employed/llc-filing-as-a-corporation-or-partner...
