Remove Spotlight Icon in the Menu Bar for macOS Mojave

1. Hold down the Command (⌘) key.
2. Hover your mouse cursor over the icon you want to remove.
3. Holding down the left mouse button, drag the icon out of the menu bar and onto the desktop.
4. Let go of the left mouse button.

Plan B: use a third-party app. Try Vanilla. You can rearrange, hide or remove menubar icons. Works while the app is running and user changes will persist after restarts if you add it to your Login Items, in addition to quitting and restarting the app. Some options are only available in the paid version (Vanilla Pro).

All icons showing:

Most icons hidden:

Spotlight icon removed:

Yes. Thus "Plan B". The choice is between living with the Spotlight icon or using a third-party app. My post reflects the usefulness of a third-party app as a suggestion. The OP can decide which choice suits him best.

Yes, uncheck "Show Siri in menu bar" in System Preferences > Siri.

Sorry, Not awake. Not to my knowledge, no.

That doesn't work in Mojave. Did you try it?

You're correct.

did you try with SIP off?

Did you?

No. Baked into the menu extra's when the operating system is compiled.

Thank you.

Did you read the original post?

"Is there any way I could remove the Spotlight Icon in the Menu Bar without using third-party app?"

My guess is he already decided he didn't want to use a third-party app since that is what he said. Perhaps English is not your first language? Sorry if it's not.