composer install
Create your .crt file based on your .pfx certificate file. The command is just below.
Put .pdf file named source.pdf on root directory.
Run using the native PHP server:
php -S localhost:8000
Open the address on navigator. The signed .pdf file it'll call output.pdf.
.pfx certificate to .crt file:
openssl pkcs12 -in PFX_FILE.pfx -out CERTIFICATE.crt -nodes
The command above needs the certificate password.
This repository was created based on TCPDF project.
All credits to them.