Am I able to partition my internal SSD safely without loss of data? I'm new to the Mac. I am wondering if it's safely guaranteed that I can make a small partition on my active internal hard drive that already contains data and apps, and then delete said partition (later on) so that the drive resorts back to its original size. Without any of the content/data affected. Is this commonplace or are there any safeguards I should put in place (other than backing up the SSD, of course)? Is there a difference based on the file system? 

The partition format could be:

Mac OS Extended (Journaled)

Apple File System APFS

MS-DOS or Ex-fat
I am wondering if it's safely guaranteed 


No.  Period.

Nothing is "safely guaranteed." Generally speaking (as at the time of this answer your question is lacking in detail), you can (re)partition without corruption of your data.  That's not to say the process is infallible.  Problems happen, mistakes can be made.  This is why is so important to have a backup of your data.