Individual organizations will each have their own guidance on redaction.
The usual process is to remove all elements that cannot safely be shared publicly.Generally, if the redacted document becomes effectively unreadable, it should not be shared.
If you're redacting a document for personal use, the following list will give some ideas of information you should consider redacting:
Bank account details and other financial information
Your address
Your phone number
Personal information such as date of birth
Your email address
Your full name, and any previous names
Social security or national insurance numbers