Sending password plain text in POST body is safe? [duplicate]

I recently started learning about pentesting, and I tried to see the request body of a website that I use frequently, and that’s what I saw:

u

(“senha” means “password” in portuguese and “entrar” means “to enter”). My question is: Is this a correct approach? I mean, can someone intercept this data and get my password? And how could this be possible?