To edit the category and tags properties of products in bulk:
1. On the product listing page of your store Admin area (Catalog -> Products), select products you want to edit using checkboxes.
2. Click Bulk edit selected -> Categories and tags.
3. In a window that opens:
specify a category/tag value you want to change (you can specify more than one value);
select the action you want to perform.
4. Click Save changes.