The masculine form for testatrix is testator. A testator is a person who makes a will.

Yes, it is possible for a testatrix to misspell her name on her will. However, it is important for the misspelled name to still clearly identify the testatrix to avoid any confusion or legal challenges regarding their identity and intention when executing the will.

A woman who has made a legally valid will before death.

A woman who has made a legally valid will before death.

The female version (seldom used today) is "testatrix."