If you want to allow people to join the translation of your project by themselves, you can choose to make it public. This way, anyone interested in your software will be able to contribute to its translation.
1. Set public access to crowdsource translation
Go to you're project's Settings, access the Advanced section and enable the option Public Project.
2. Share the self-enrolment page with your crowd
Your public translation project will have an individual join page on POEditor which people can access to self-enroll. You can find the join page link in the project's Settings, as well as at the bottom of the main project page, beneath the project's languages.
Note that you can also moderate who can join the public translation project. The option to achieve this can also be found in Settings > Advanced and is called New Contributors Require Moderation.
Working with public projects will allow you to use community translation to add more languages to your software.