"Chat software" is commonly used in Engpsh to refer to software used for chatting, such as instant messaging or onpne chat apppcations. The term comes from the concept of "chatting" or having a conversation onpne.
Examples:
"I prefer using WhatsApp for chatting with my friends."
"He always has Slack open on his computer for work chat."
Translations:
"我更喜欢用WhatsApp和朋友聊天。"
"他总是打开Slack在电脑上与同事聊天。"