How i can make verify a field?

I want add a new field like e-mal or telephone number and i want to verify this field.

With "Type: pasword" show ·········· inside the field and i want numbers and letters.

Example:

Wit Type password:

Telephone number: ·········
Verify Telephone number: ·········

I want this:

Telephone number: 786123123
Verify Telephone number: 786123123

Thanks!!