Bikes come in different frame sizes for different size people. The nominal dimension is between the handlebar stem and the seatpost, typically 18", 20" and 22". I suggest you read the reviews on the main site and focus your shopping on the bikes that have the shorter dimension frames. 18" bikes tend to fit me, I'm 68" tall and also age 68. Cort also publishes a "step over height" which has something to do with whether one can touch the ground from the seat.
The previous two posters have tried to direct you into a 20" wheel bike. While these have excellent stepover height, they ride rather roughly IMHO plowing through potholes and over speed bumps. Although i have short legs, 28" pant inseam, I prefer a 26" wheel to smooth out the bumps. I also prefer 2.1" tire cross section, or 55 mm. Fatter tires are quite expensive, difficult to change on the road, and a magnet for thieves since fat tire (3" up) bikes are popular now. The 2.1" Kenda tires are smooth enough for me, and the ones with knobs resist puncture well enough as long as the knobs are still tall enough. One city tires on the bodaboda went flat after 700 miles, but the knobby kendas I replace them with are over 2000 miles already. I can flip the bike over & change a tube in under an hour.
The bike left in my avatar achieves those goals, easy to get on & off at stops, plus a decent ride: a yubabikes bodaboda. Unfortunately you can't buy it with electrical drive anymore. I e-converted mine from a human powered bike by installing a $189 1000 W power wheel, controller, and throttle, and a $730 17 AH battery. I prefer the generic 48 v battery & 135 mm dropout power wheel, as those parts will always be available for the rest of my life time anyway. I also prefer hub drives as being capable of being pedaled even with the power off. My bike weighed 63 lb before I put the motor battery and racks on it.
Major vendors that probably won't go broke in the next 3 years are juiced, pedego, magnum, raleigh, trek, rad. Cort doesn't review trek. I don't like the 7 speed derailleurs on rad and other bargain brands, I've broken a shimano 6 speed axle at my terrific weight of 170 lb. Shimano 8 speed has thicker axles and probably better steel.
Happy shopping. I have to say, shops tend to not stock bikes in the smaller frame sizes. I had to buy the bike left over the internet, based on the dimensions. The drop frame is the smaller one, for people 63" tall and up. I have had trouble lifting my foot over a straight bar at least since age 63. One can find 18" frame bikes in discount stores made up for children. Unfortunately they have kiddie grade components like rim brakes and 7 speed thumb shifters. One can try the frame on for size, perhaps, without buying it.
For example, reviewed today, the specialized turbo como step through frame
https://electricbikereview.com/specialized/turbo-como-4-0/
comes in a 15" frame size and weighs 49 lb. Minimum saddle height is only shown for the 19" frame in the review.