Oh, yes, you are going to want something with a smaller size lithium (something with "Li" in the battery chemistry designation) based battery chemistry for weight reasons. You do not want one that uses lead acid (SLA) batteries, they are really heavy and not suited for folder use much less for a small person who can't or doesn't want to lift a lot of weight. Almost any battery size with the exception of the very, very smallest ones that are shaped like a bike water bottle and fit in a water bottle rack should be sufficient for your needs so look for a small but adequate battery. A 5 to 7 amp hour (Ah) frame or rack mount battery should be more then sufficient for your needs.

If you don't want to have to pedal you do not want a bike that has a "PAS only" controller system. Some "pedal assist" (PAS) systems have an over-ride where you can turn just push a button or twist a throttle on the handle-bars some do not and the motor will only run when you are pedaling. Read the description carefully to see which kind of controller system the bike is equipped with. Some bikes use just a simple throttle control on the handlebars which works just like a motorcycle throttle or car accelerator pedal and has nothing to do with the pedals, some controllers have a PAS system with a sensor on the pedals that turns the motor on whenever you are pedaling usually with two or three different select-able levels of assistance of those some have a manual throttle over-ride and some do not. The ones that do not are "PAS only" system. Read the description carefully to figure out what kind of controller system the bike uses otherwise you could end up getting a motor control system that is not what you want.

Okay, that's my advice as far as what kind of components to look for as far as motor, battery, controller. Also as to pedal gearing, If you like to pedal your going to want a rear derailer gearing set-up (usually 6 to 8 speed). If you don't like to pedal and are mainly just going to use the motor then a single speed gearing is just fine and would probably be preferred.