How do I connect an external microphone to my iPad 10th gen?

Assuming that your microphone has an appropriately wired 3.5mm audio plug, you may be able to connect the microphone to your iPad10 using an Apple USB-C to 3.5mm Headphone Adapter:

• USB-C to 3.5mm Headphone Jack Adapter

https://store.apple.com/xc/product/MU7E2ZM/A

While this adapter is primarily intended to connect wired headphones or earbuds (with microphone) to your iPad, a correctly wired microphone can be connected. Here is a diagram of commonly found 3.5mm plugs; the microphone must be wired to the CTIA/Apple standard:

There is no native process to do that.

If you have an App installed that supports the microscope, and a Microscope that supports iPads, then follow the steps in its own user guide for how to connect it.

Some attach over the the iPad camera, others may use the USB-C port.

Each microscope would be different.

At least provide the make and model of the microscope and someone may be able to advise.

Sorry, I read microscope, not microphone.

In any case, similar answer, If USB-C it may be able to be connected directly. Otherwise, you may need an adapter of some type depending on what connection the microphone has.

Again a make and model would be useful for more specific advice.