Formatting means boxes and type, not animation
People search this phrase when a cheap tool reflowed a table. We keep slide geometry. We will not keep click sequences. If a chart is a live OLE link to a missing workbook, nobody can save you.
Fonts
Embed in PowerPoint. Substitution is how brand decks look “off” even when boxes align.
Masters and footers
Slide numbers and logos usually survive. Theme fonts need to be present on the worker, or embedded.