It depends on your hosting plan.
Essentials plans use a curated plugin set. You cannot install arbitrary third-party plugins yourself on Essentials because the shared managed platform must remain stable, secure, and supportable.
Premium and Enterprise plans provide more flexibility for custom Moodle plugins and themes. Premium plans can support custom plugin and theme installation. Git Integration is a separate optional add-on for deploying custom Moodle code, plugins, and themes from your own repository. Enterprise plans can include custom development, integrations, and implementation support as part of a wider scope.
If you need a plugin, send support the plugin name, Moodle plugin directory link, business purpose, and whether it is required for launch. The team can confirm the right plan or implementation path.