And the letter header is not coming in pdf.
am I right?
If not coming letter header then you install erpnext manually or not?
If manually installed then apply it.
wget https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox_0.12.6-1.focal_amd64.deb
sudo apt install ./wkhtmltox_0.12.6-1.focal_amd64.deb
for the wkhtmltopdf upgrade.
Thank You!