USB to Serial
ESP-12 is the most common Wi-Fi module format nowadays. The same footprint is used by Tuya (TYWE3S, WB3S, CB3S, etc) and other manufacturers which are not using Espressif chips. Because of that a simple module swap is the most straightforward way to install Tasmota on such devices.
Read my guide on replacing a compatible module.
ESP-12S and ESP-12L modules have those pins already pulled internally. It is recommended to choose this version for easier installation.
ESP-12E and ESP-12F modules need the GPIO15 pulled low and CH_PD or EN pin pulled high to boot.
Serial Flashing ESP-12L and ESP-12S
Serial Flashing ESP-07, ESP-12E and ESP-12F
You can purchase (AliExpress, Amazon, Banggood) a test board for effortless flashing.