For https:// you will need to purchase SSL certificate from any third party provider like Godaddy, GeoTrust etc.. They will send you certificate files then you can share those files with us and our team will install the certificate on your website.
One important thing to note here is that our team will need all appropriate permissions to install this certificate through Cpanel or SSH client. So, you will need to grant us these permissions from hosting. For more queries related to permissions, please check with your hosting support.
For SSL installation, we should recommend client to get it done by hosting company if they can do it.
2nd Option can be FATbit doing it for them for additional charge.