As to the first stamp you show, we usually recommend that those seeking to identify US stamps make themselves familiar with the Stampsmarter website. In this particular case, you have a stamp from the so-called Washington-Franklin series and there is a distinct and very helpful tool at Stampsmarter that you can use:
https://stampsmarter.org/features/S...rank_ID.htmlThis will help you step through the identification process in an orderly fashion, beginning with the design, denomination, then perforation.
For that you will want to get a perforation gauge if you do not already have one. There is a printable one at Stampsmarter.
It appears to me that your stamp is perf 12, but you should use a gauge if you have not done so before. Unfortunately the perforations at the top are badly damaged, but you can just use the gauge on a side for this particular stamp.
With the perforation known, you then look at the Stampsmarter chart.
We know it is not a coil stamp (with two parallel unperforated sides), and it does not appear to be on the so-called bluish paper, so there are left two possibilities, shown on the chart: a 332 or 375.
So here too you will want to check the watermark of the stamp paper.
Learning to sleuth these out provides hours of interest in the hobby so we hope you will pick up a perforation gauge, get set up to do watermark detection, and start to dig in with us.
Do post back if this explanation doesn't make enough sense. And welcome to the forum....