Welcome!
I keep a drawer in my desk just for my garden. An envelope there gets receipts. Another gets all the plant tags. I keep packets of seeds in there (cool and dry).
I have a notebook I keep in there that I jot down notes, ideas and phone numbers of nurseries. I keep a list of all the things I plant. All my daylilies are numbered with tags and those are recorded in the notebook. So if I'm out in the garden I just take it out with me. Occasionally I clip a picture from a magazine or catalog and tape it in the notebook. More like a scrapbook than a journal. I have all the plants in each bed listed together so I know where to find what.