When it comes time to collect your seeds throughout the summer and fall, you could pay to buy those fancy seed envelopes like these. I use something that’s free, but if you want to sell your seeds or give them as gifts, these ones by Proterra are neat, and it appears you can even put them through your printer.
I used the extra envelopes I get inside bills or donation requests. Just label the front, insert and date the seeds, and then fold the flap down, and bend both top corners backward toward the flap side to keep it shut. There is no need to seal the envelope.