You'll be looking at a minimum of:
Intel Core i3 Processor/graphics
4Gb RAM
SSD hard drive of the size you think you need
Stay away from the usual consumer oriented devices (which is what you will find on the high street), such as HP Presario and Dell Inspiron.
Also, a decision needs to be made on portability. There are basically 3 main styles/sizes:
The larger type, with larger screen, and the keyboard has a built in numeric pad to the right. Tend to be heavy and large, not ideal for always on the move, but larger screen and full keyboard make them nice to use if portability isn't a major factor. eg
https://www.ebuyer.com/842464-hp-250-g6-i3-laptop-4qw30ea-abu (note, I'm not recommending that, esp as that lack an SSD)
The medium type, slightly smaller screen, no numeric pad on right. A very good compromise. Reasonably portable. eg
https://www.ebuyer.com/831702-hp-probook-440-g5-laptop-3vk35es-abuAn Ultrabook. Smaller screen again, sometimes a slightly smaller keyboard (might throw touch typists). Very portable, and generally better built and robust. Also a lot more expensive. eg (ignore price)
https://www.dell.com/en-uk/shop/laptops-notebooks-and-2-in-1-laptops/new-xps-13/spd/xps-13-9370-laptop/CNX37016?ref=p13n_system_pdp_eol&c=uk&cs=ukdhs1&l=en&s=dhs(Note, defo not recommending any of the above specifically, thats just to give an idea).
Obviously, the ladyboys amongst us might also suggest Apple MacBook. But these are around £2k for useable ones, and don't run Windows applications (easily)
With that choice of size/style, and the spec at the top, thats you're starter for 10
For Word processing, there are free apps that are half decent. But if she's used to Microsoft Word, MS Office variants start at around £80, or as a subscription from £6 per month (which a bunch of online storage thrown in)