How to change validation in opencart?

Question

opencart

Version 2.1.0.2.1, it costs neoseo, but the name field skips numbers when filling out the form, I would like only letters, confused where exactly this can be fixed and the author's question, there are forms where there is a mask in the phone field, but there are forms , where it is not there and there is an international mask, how to change it so that the usual mask is displayed and where? Thanks