Apple Watch 8
Why doesn’t the adapter to charge the watch fit into any of my usb ports. Have an I phone se. Wasn’t told I needed a special usb
The current range of Apple Watch are all capable of fast charging with their supplied charger when it is driven by an approved USB-C power adapter. Your watch can also be charged by the older USB-A type chargers if you have one around from a previous Apple Watch. However, to reflect the current rend for eco-usage, waste reduction, and for reduced cost Apple does not supply a power adaptor with each device because many customers already have many power adapters which can be used.
If you don't have a matching pair of charger and power adapter, you seem to have a choice. You can add either a suitable USB-A cable which will fit your existing USB-A power adapters,
Apple Watch Magnetic Charging Cable (1 m) - Apple
-or-
you can add a USB-C power adapter which will work with the new Watch Charger cable. Without knowing where you live around the world I can't suggest the exact type for wall plug matching, but my generic options would be the 20W charger
Buy 20W USB-C Power Adapter - Apple
-or-
The 35W dual port charger, because I love the one I have for charging 2 devices when I travel
35W Dual USB-C Port Power Adapter - Apple
I think those links should give you the general idea and point you at a suitable solution but you might have to search a little to get your local version in your home currency.