This brief note is not legal advice and is for educational purposes only.
The USPTO requires Figures or Drawings to be on either 8.5”x11” or A4 (210 x 297 mm) pages. There also must be margins, meaning you can’t use the whole sheet/page edge to edge. MPEP 1606 and 37 CFR 1.165 covers plant drawings, while 37 CFR 1.84 covers Standards for drawings.Fiducial marks (e.g.target points, cross-hairs) are not required.
Just keep your figures within the boundaries illustrated below and you should be okay. Here’s a summary in visual form of the margin requirements (not to scale).
Like you were told as a young child – stay within the lines and happy drafting.