I need some legal advice so I can start a small online business! (People with particular experience/lawyers would be appreciated!)

I am looking into starting an online store in which I sell hand crafted greeting cards and mail them out to customers. I don't have any employees, and I don't plan on it getting too big, so I am the only operator of this business. The only thing I will be selling is greeting cards in which I make on my own. I need to know how I can LEGALLY do the following:
Maintain my online presence as a "business"
Be able to sell and distribute products
Collect payment from people for above said "products"

If anybody could give me some help or needs information please let me know! Thank you in advance!