Does Mac allow deletion of files?

Hello,
I'm a fairly new user of Mac OS. On windows/PC based systems I used to be able to delete files to free up hard-drive space. My friend told me that I could do the same on a Mac. Earlier today I deleted over 100 gigs of files, but the storage tab under "about this mac," shows no parallel amount of freed space, nor an increase in "other." In fact it shows the exact same breakdown as before. I'm surprised that there exists an option to make files inaccessible (i.e. empty trash), yet have them still take up space on your hard-drive. What is the purpose of this feature? Am I missing something?
Thanks in advance,

- J