Following are some guidelines for initiating & reviewing a PR to have a common understanding and make the process easy for all the teams involved.
Before posting a PR
Make sure that the implementation is complete and the acceptance criteria on the ticket/issue are completely met
Try to distribute the code changes into atomic commits making it easy for the reviewers to review the changes commit by commit
Posting a PR
Follow the pull request template (if any)
Add a detailed description to the PR including screenshots, videos, config changes required, ticket/issue link
Make sure all the checks pass on the PR (i.e. all test cases pass)
Add relevant reviewers who will review the PR
Reviewing a PR
Checkout the code and run the app to see if the implementation has been done according to the ticket/issue
Review the whole PR and then post a review including your manual testing and code-related feedback
In case there are multiple commits or the PR is big, do mention in the review if the review pass has been done on certain commits or if it's incomplete