Is a wife entitled to search her husband's phone with his permission, and what should she do if she discovers his lies, and what is the ruling on a husband speaking with his female colleagues via their private phones to save money?

A wife looking at her husband's mobile phone is forbidden if he does not approve of it, because it is espionage. However, if it is with his consent, then there is no objection to it.

If the wife discovers that her husband is lying, she should explain to him the ruling on lying and advise him to abandon it.

A man speaking with non-mahram women over the phone is permissible out of necessity, with Sharia-compliant controls, and he should avoid working with women unless there is an extreme necessity.

Using a work phone for private calls is not permissible if there is a financial cost associated with it, because it is using work tools for purposes other than what they were intended for. As for using his private phone, there is no harm in it as long as it is not an illicit use.