If you are using the full version of Acrobat DC, follow this link for a full walkthrough: Add a stamp to a PDF in Adobe Acrobat DC

Convert Picture to usable PDF

1. Find the image you want to use as a stamp or create one
   
1. The image format can be anything at this point
   
2. Save the picture to a location you can easily access
   
1. This won't be the final location
   
2. You will probably want to delete it when done, so the "Downloads" folder is the best location
   
3. Right-click on the picture and "Edit with Paint 3d"
   
4. Crop the image down as to get rid of any unnecessary white space or other images outside of your image
   
5. When done, Menu > Print > 2d Print
   
6. Use these settings
   
1. Orientation = Either Portrait or Landscape, whichever your image fits better
   
2. Paper size = Statement 5.50" x 8.50"
3. Scaling = 50%
4. Alignment = Center
   
5. Leave the remaining as default
   
7. Print
   
8. It will ask you where you want to save your PDF
   
1. Recommend downloads folder as well, but best to do the same place as your original image
   
9. Save
   
10. DO NOT EXIT
    
1. Best to leave this open if you need to resize it later
   

Crop PDF

1. Visit Crop PDF files online - PDF Tools (pdfresizer.com)
   
2. Choose Files
   
1. You only need to choose one
3. Browse to your file and select it
   
4. Upload files!
   
5. Create a box around your image and resize it as necessary
   
6. Once done > Crop it! > Download
   
7. Save to the final location you want to keep the file
   
1. We Recommend either a shared drive or your personal drive
   

Create Stamp in Acrobat Reader

1. Open a file in Adobe Acrobat Reader
   
1. The file doesn't matter, but one you want to stamp is best
   
2. In the top left, click Tools
   
3. Underneath "Stamp", click Open
   
4. Custom Stamps > Create
   
5. Browse... > Locate the PDF file you cropped earlier > Open
   
6. OK
   
7. Options
   
1. Category: You can choose to create a new category or choose one from the drop-down
   
2. Name: memorable name for your stamp
   
8. OK
   

Using the Stamp

1. With the PDF Open > Tools > Stamp > Open
   
2. On the Stamp toolbar, choose Stamp
   
3. Choose the category your stamp is saved to
   
4. Click on your stamp's name
   
5. Click wherever you want your stamp to go
   
6. From here you can resize and move the stamp to wherever you want
   
1. It behaves just like a picture