The Certificate plugin is a very useful program that you can configure so that it issues a PDF certificate when the learner completes with a passing score (which you select) for the activities that you've selected.
This plugin allows you to customize the PDF to a certain degree and to select from four pre-designed options. You may include the name of the course, the date, and also the name of the organization awarding the certificate.
You can download the plugin from this site: https://moodle.org/plugins/mod_certificate .
If you are using Moodle 3.0 or higher, you can use this link: https://moodle.org/plugins/download.php/9988/mod_certificate_moodle30_2015111601.zip .