Product Builders need to have a clear idea about why, what, how and for whom they are defining a product. Your team and stakeholders will also want to understand why and what will need to be built. A product requirements document has been proven to be a very useful doc for product people and stakeholders to all build in the same direction, with the same understanding of the goal.
I start every product discovery phase for new features or entirely new products with a basic outline, the template copied below. If you keep using the same template and questions in it, before long you will internalize them. The beauty of internalizing this template is, that it gives you a framework that will help you during product discovery, product presentations and product development discussions. Make it your guide while you gather product requirements.
The questions in it usually spark the right thoughts and details to be added. Questions that your team or stakeholders will ask you.
I aim to keep it comprehensive and included all sections I have used in the past. Not all sections are always relevant.
Feel free to copy this template for your own products. Let me know how you like it and what your favorite template is.