There is an option on table views to Customize the fields that are shown. This field is available on the Web and iPadOS clients, but not the iOS client.
Even though the iOS client does not show this option for some reason, it is also not honoring the settings made in the other clients. For example, if I hide a column in the web client, this is carried through to the iPadOS client. However, the iOS client still shows the hidden field.
Maybe space for the option is an issue in iOS, but that does not mean that the client should not apply the setting as defined in the other clients.