If you only need the printer to work with Windows/Linux/Android:
Search: TP SK713S driver download → Look for .inf or .exe driver files, not firmware. tp sk713s pc822 n firmware download
Warning: Do not download firmware from random file-sharing sites or unverified blogs. Many "firmware download" pages are scams or contain malware. If you only need the printer to work
Realtek drivers are often generic. If the device uses the RTL8188EUS chipset (common for SK713S), the driver is widely available on Realtek's consumer download server. Search: TP SK713S driver download → Look for