Hello and welcome to yow. Glad to hear you are going to buy a bike. A hybrid would be a good choice for canal footpaths and the like and would still be fast enough on the road. A 'hybrid' is a cross between a mountain bike and a road bike, so you get an upright position and heavier duty wheels and tyres. Expect to spend from about £400 on one. Find a good bike shop who will be able to advise you and select the right size. Buying on line or from
Halfords might be more problematic, although H's have had some good press on here. Good luck.