Put the PULL_REQUEST_TEMPLATE.md into the root of your repository. Github will now make its content the pre-filled default for new Pull requests.

The template is opinionated set of sections that proved to cover necessary information for a big, ongoing project managed by multiple teams over the span of multiple years.

Its goal is to provide enough information for anyone combing trough Git history and PRs, trying to discover why a change happened and what was the context.

If used properly, it can even help in case of Ticketing SW switch as it encourages developers to fill in (replicate) notable details from the ticket itself, which can later save the date if the links to old ticketing SW go dark after the switch.