I want open Face ID so How can i do ?

Hey there,

See ☞ If Face ID isn't working on your iPhone or iPad Pro - Apple Support

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See ☞ If an alert says Face ID has been disabled on your iPhone or iPad Pro - Apple Support

if you are seeing the alert from the article you came here from (related article at the top of the page), then follow those instructions. If your phone is up to date, then as #2 indicates, you will need to bring your phone in for service