Hi @abgago_2000,
It is possible to get a certificate without being able to install software on the server side. The inconvenient thing that you should be aware of is that the certificate lasts only for 90 days, and you’ll have to repeat the process of obtaining and installing it every time that it’s due to expire. Assuming it requires some manual steps, those steps will have to be repeated every time. That is possibly frustrating (or easy to forget to do) compared to cases where you can install software on the server that can take these steps automatically.
Depending on your operating system and your level of experience with system administration and certificates, you can install client software on your personal computer and use it in a “manual” mode (where you have to make certain changes to your web site at requested times to prove that you control the domain). Or you can use a web-based client which will walk you through this process inside of a web page.
Your main web-based client options are https://zerossl.com/ and https://gethttpsforfree.com/.
The last step in the process would be an option to download and save the files that your hosting provider is expecting.
See also List of Client Implementations for other software options that you might be able to download and run on your own computer.