To delete a supplier, navigate to the Contacts screen and select the Suppliers table.
To delete suppliers, select each row you want to delete and click on the trashcan icon on the top right of the Suppliers table.
You can also delete a supplier from the Supplier card by clicking on the three-dot icon and choosing Delete.
If a supplier was used on any (O)POs, the supplier info won't change on those orders, but the name will have a strikethrough. You can't choose a deleted supplier for any new orders.
Only Owners and Users with the Delete suppliers permission can delete suppliers. Read more about the permission.