If your child has created work outside of Seesaw that they would like to share with their class teacher they will need to turn it into a PDF in order to upload it.

1) Save a normal copy of your work

2) Find the 'Save As' option

3) Change the drop-down menu underneath the file name to PDF

4) Give your file a name and save it somewhere you will be able to find it

5) You can then use the upload option on Seesaw to share your work

Info from BetterCloud