I’m Melissa, a Shopify Guru. Thanks for reaching out. The title tag can be set for pages, products, collections, and blog posts using the Shopify admin. Each title should be unique. You can access the Page title for a collection by going to Products > Collections > Choose the collection you would like to amend. Then once in the collection page if you scroll down to the end you will see something like this screenshot here. This is where you can edit the description and set it all up for SEO.
Some things to note when editing the SEO and Page titles:
Hope this information helps! You can reach out to the Guru team https://help.shopify.com/questions if you have any questions.
Have a great day!
Melissa | Shopify Guru