Change font size in Adobe PDF, you can use the In Print and Add Images to PDF tools. Step 3. Adjust Font Size in PDF to Custom Size You can also change the font size of an existing text as follows. In the 'Text' option, double check that both options are displayed. Then click on the 'Change Color to Size' icon to adjust the font size. 1. Select the existing text. 2. Change the font size using the above two options. 3. Then click on the 'Add an Image to PDF' icon to show an online tool to add a picture to the current layer. Now you can view the newly added picture and its size. (Click on the image below) Change in Font Size of Existing Text Use the tools given below to change the font size of the text You can see the picture below and its size. 4. Add Image to PDF With the addition of text to the PDF, you can now add images in- place to the text. Click on the Add Image to PDF option in the top menu. Choose the folder you want to add as the source, click on the 'Add...' button, and click on 'Add Image'. How to Change font in Adobe PDF to OpenType To change font in PDF, you have to follow these steps: 1. Choose 'PDF' on top menu 2. Click 'Change Font' 3. Choose the option that you want to change the font size within PDF to use. Change the font size using 'Change Font', then select the existing font and click 'Add Image to PDF'. Choose the source of the image, and click 'Add...' . 5. Change font size in Adobe PDF to OpenType (TTF Font) You have to use the tools given below to change font in PDF, in Adobe Illustrator. For this font to work, you also need to add 'Changeling to OpenType font' in the PDF file as a layer. 1. Change font size in Adobe PDF to OpenType TTF Font 2. Choose from the available fonts, then Click 'Change Font' to change the Font Size.