You cannot do that in Premiere Elements.
What program are you using?
Please give details.
I have Photoshop elements
Just open the file in Photoshop Elements, select File/Save As and save it in whatever format you'd like, including PDF.
However the file will not be a vector file, as Photoshop Elements is a raster, not vector program.
Adobe Illustrator is a vector program and has some tools for tracing images as vector objects. However, there is not magic way to turn a raster image into a vector without essentially recreating it.
Thanks for the follow up with the important information on what program is involved.
If your program is Photoshop Elements, in the Full Editor, you can (as mentioned) save the file as a pdf file, using Photoshop Elements' File Menu/Save As and then select Photoshop PDF.
Since your program is Photoshop Elements, please take advantage of the specialized expertise in the Adobe Photoshop Elements Forum.
While there, please give details such as Photoshop Elements version number and computer operating system for troubleshooting purposes.
Somehow your thread got posted in the Adobe Premiere Elements Forum (video editing).
Best wishes moving forward with your projects.