How can I lock my lost iPhone as locked to owner?

I think you would want to mark the phone as Lost, as outlined in the Apple Support document to which Neil linked.

"When you mark your iPhone or iPad as lost, your device is put in Lost Mode — it's locked with a passcode, payment cards and passes that you use with Apple Pay are suspended, and you can display a phone number and message for someone who finds your device."

To be on the safe side, if you decided to have the phone display a phone number and message, you might want to have it display the phone number for a local police station, and instructions to leave it with the police. Or another safe, neutral, place (like a Lost & Found department at a shopping mall).

Beware of "phishing". Thieves and fences who obtain contact information through any means may send messages claiming to be from "Apple Security" or the "police" or some such. These messages are not from Apple, but from criminals seeking to trick you into releasing Activation Lock and/or disclosing credentials that the criminals can use to get into your phone, and ransack your data.

Do's and Don'ts for lost iPhones - Switched Off - Offline - Beware of Phishing – Apple Community

Click here for information; in addition, post notices around where it got lost, and if applicable, contact the Lost & Found department of the facility involved.

All the options for locking it are available through Find My or by asking your wireless carrier to blacklist it.

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As long as your Apple ID was signed into your phone and you used a Passcode to lock it, then it is already locked to you. Anyone that finds your iPhone will not be able to reset it to use the device.