This is the same as a file copy. How would you copy a file from Server A to Server B?
You want security. Even if this is your music CD database, someone will hack it and mess with you for fun. So you need a VPN or secure share method. Even Dropbox would work if these are small files.
The process is that Server A (source) creates a file. Then Server A or Server B can copy the file to a new location. This is the same as any file copy. Then Server B restores the log backup to it's database. The part across the Internet is how to share a file across the Internet. There are multiple ways of doing this, but it's hard to say "do it this way" or "here's a tutorial". Ideally you would have a VPN and just let a normal file copy occur between two windows machines.
There are tutorials for log shipping. You should understand how this works: https://docs.microsoft.com/en-us/previous-versions/sql/sql-server-2008-r2/bb510542(v=sql.105)