Hey there, @Corina7506
Bo here from Shopify Support!
It sounds as though you may need to make your products available on these sales channels. You can control where you are selling a product by making it available to your active sales channels. If you decide not to make a product available to a particular sales channel, then it will be hidden from that channel's product catalog. To view or change a product's availability settings:
You can also set product availability by channel as a bulk action.
Once your products are made available you should be able to see them in your Facebook catalog an be able to tag them on Instagram.
Let me know how this goes and if there is anything else I can assist you with, I'm happy to help!
All the Best,