how do i scan legal size documents?

Do you have a scanner?

If so, does it support legal size scanning?

If not then try an office store or public library to see if they can scan legal size documents.

An office store like Staples can do it for you for a small fee, bring a flash drive with you for them to put it on.

If your scanner is too small to scan your legal size document in one pass, you can scan it in two or more passes and combine the scans in Word, InDesign, or some other program, then export to a new PDF.

Photoshop has an effective tool to seamlessly combine images- File> Automate> Photomerge. This is handy if you need to scan a photo in sections and then recombine.

Use a scanner and scan the documents.