Build a form for online completion of a legal will

We have a legal will that we use which is currently completed manually using Word. We want to automate much of the form filling online by the user and hopefully make the will process completely automated. The form would include inputs for names of certain individuals (testator, executor, beneficiary), but also various options for different ways to structure the will. For instance, a gift to X of $y. Or the establishment of a trust under a will. These are simply distinct clauses in the will precedent we use and we can replace clause as needed. Would also need a definition section which links key terms to unique identifiers.