Hello,
Just purchased P365 with manual safety option.
Have a question. Can't use this option until the bullet in the chamber. Is it how supposed to be? Please let me know if you know - Thanks

See Page 47 of your user's manual. Part of the pistol's safety check procedure is to put an empty magazine into the pistol, rack the slide back to the rear, drop the magazine, use the slide catch lever to send the slide into battery, engage the manual safety, and then pull the trigger. If the trigger won't let the striker go forward, the manual safety works properly.

thanks a lot. Just checked page 47 - works great.

Generally one removes the magazine first, when doing a safety check (in most pistols). Just make sure that magazine and chamber are empty...check twice.

Safety check with a loaded chamber? Don't do that.