You can control which collections appear in the collection filter on your order form. To do that, first, make sure your Product Restriction is set to Show Collection To. If not, the below article can help you change the setting.
To show a collection to specific customer groups:
- Go to the collection you want to show and click the dropdown under Show Collection To.
- Select a customer group from the drawer to show the collection to,
All Customers— Everyone will see the collection on the order form dropdown filter
No Customers— No one will see the collection on the order form dropdown filter
Logged In Users— Only users who are logged in will see the collection in the dropdown
Customer Tags— Select a list of customer tags who will see the collection in the dropdown. Here's Shopify's guide on tagging customers.
- Click Save.
To show products too, follow the instructions in the article below,