If I reset my iPhone 11 will I lose my data?

el7ntk wrote:

If I reset my iPhone 11 will I lose my photos, contacts etc?

Only if you do erase all contents and settings.

Depends on what you mean by "reset". But a restore to factory conditions will basically wipe all the data from an iPhone and bring up as if it were a new iPhone out of the box.

Some people do that (I've done it myself) but back up and then restore that backup to the iPhone. There are various reasons for doing that (especially purging temporary storage that isn't released).