How can I recover iCloud of lost phone

Turn on lost mode in iPhone Use Lost Mode in Find Devices on iCloud.com - Apple Support

Use your Apple ID and password to get signed in at www.icloud.com from a web browser How to sign in to Find Devices on iCloud.com - Apple Support

And then archive the iCloud data Archive or make copies of the information you store in iCloud - Apple Support

Greetings James_kate,

If the steps included in the related article above your post have not resolved the issue, the next step will be to Contact Apple Support directly for further assistance.

Take care.