Unable to e-sign IMM5983 Canadian Immigration Form

I am unable to e-sign this form. It requires signature from two different parties and it is not the usual form where we click on validate. No matter what I do - I cannot electronically sign it. Please help!

If the attached file doesn't open then you can find the link to this form here:

https://www.canada.ca/content/dam/ircc/documents/pdf/english/kits/forms/imm5983e.pdf

Thanks in advance.