Method

The smallest document that answers the question

Start from what was asked rather than from what you have. The two are rarely the same size.

Someone asking for proof of address wants one page showing a name and an address. Someone verifying a single transaction wants the page it appears on. In both cases the rest of the document is noise at best and private at worst.

When a page holds two things

Sometimes the line you need shares a page with lines you would rather not share. Splitting cannot help there — a watermark or a redaction in another tool is the answer, and sending a photograph of the relevant part is a legitimate option nobody mentions.

When the recipient asks for everything

Then send everything. The point is not to send less on principle; it is to send what was asked for, deliberately.