The Raspberry Pi Pico W is perfect for IoT and wireless projects, better still, it's such an affordable 32-bit microcontroller that is packed with peripheries including WiFi.
Raspberry Pi Pico W - the W at the end stands for "Wireless" and supports WiFi 802.11n 2.4GHz out of the box along with BLE in the future. Best of all this board is manufactured by Raspberry Pi, which means excellent resources and a very stable port of MicroPython.
The wireless antenna is an onboard type, similar to that used on the Raspberry Pi Zero boards. The pins are standard pitch, so it's easy to solder pins on and get going with solderless breadboards.