It’s best to use a solar PV system with a roof that faces within 90 degrees of south, as long as no other buildings or trees overshadow it.
If some or all of the PV surface is in shadow for some of the day then your output would decrease. The panels are quite heavy so you must make sure your roof can support this weight.

The panels are called arrays, which come in a variety of colours and shapes, you can get grey solar tiles that do indeed look like roof tiles, or even transparent ones that can be used on conservatories.

Remember you may require planning permission to allow you to install the PV system, always check out if this is needed first.