I thought about a small invention. Should I draw a drawing first and then let skilled workers build it before applying for a patent?

Applying for a patent does not require a physical object, so there is no need to make something and then apply for a patent.

When applying for a patent, specific technical solutions and drawings must be provided. For circuits, a circuit diagram or circuit schematic diagram must be provided, and for machinery, a mechanical structure diagram must be provided.

Draw out the drawings and write down the technical plan, and then you can find a patent agency or professionals to help you apply for a patent.