Two issues:
1. How to transfer the file from an Amiga disk to the PC
2. How to read/convert the file to a modern word processor
Problem #1 is a bit tricky. If you have access to an Amiga 1200 w/ built-in CrossDOS, it is only a matter of transferring the files on the Amiga to PC (FAT) disks. If you have a copy of CrossDOS or Messydos (freeware) on an Amiga disk, you can do likewise with an older Amiga.
If you don't have any Amiga software to read PC disks, you might try a null modem approach, which I have never used personally. On the PC side, the commercial software Amiga Explorer seems to be most commonly used.
If you don't own an Amiga at all, either find someone else who has an Amiga or get a Catweasel Mk 4 PCI (or ISA version, if you're using a vintage PC) disk controller, which is programmable to read foreign formats unlike other floppy disk controllers on a PC motherboard.
Even if you manage to transfer the files over, I'm not sure WordPerfect on the Amiga and WordPerfect on the PC used identical file formats even back then. If the files are pure ASCII text, there is no problem, but if they contain a lot of formatting, you may need to look around for various converters and cross your fingers. If you own an Amiga with suitable version of WordPerfect, you might try to export the documents to whichever different formats it supports until you find a combo that can be read on the PC.