Tell your friend, regardless of which instance is chosen, to post relevant items to these groups that are followed by hundreds and even thousands of crafters:

https://a.gup.pe/u/fiberarts (big group)
https://a.gup.pe/u/embroidery
https://a.gup.pe/u/knitting
https://a.gup.pe/u/crochet
https://a.gup.pe/u/sewing
https://a.gup.pe/u/quilting
https://a.gup.pe/u/yarn
https://a.gup.pe/u/crossstitch
https://a.gup.pe/u/spinning

And yes, top-level posts should also use hashtags. Even just one relevant hashtag in a new top-level post is good enough.

A possible instances for artists and crafters:

https://mastodon.art/

However going with a larger instance like mastodon.social will make her posts more visible in the local feed.

There are also some reddit subs with many thousands and even hundreds of thousands of crafters subscribed. For example, r/knitting has over half a million subscribers and 111 are online right now. The r/sewing subreddit has over 2 million members and 85 are online right now.

#Fabric #FiberArts #Sewing #Knitting #Quilting #Crochet #Yarn #CrossStitch #Embroidery