my iphone 8 has been stolen and cant see in find my which was previously shown

Keep in mind that the phone must be powered on and connected to the Internet for it to show up on a map.

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

You need to face the reality that IF your phone was indeed stolen - vice being simply misplaced - that you’re NOT getting it back.

FindMy is NOT going to lead you to the criminal’s hideout. (any criminal will simply inhibit FindMy)

So … follow the steps already provided in 1st reply AND be aware of the following:

= = = = =

WARNING: Going forward - in the coming days, weeks, or months - EXPECT messages from the thieves, usually claiming to be Apple (or even the police) which attempt to phish your personal info so as to be able to break into your phone and/or AppleID.

These are criminal attempts but which can appear VERY polished and convincing.

Disclose NOTHING and do NOT follow any links they might contain.

They are NOT from Apple or anyone legitimate.