Synthetic oil for toyota Yaris 1.5L

Guys I need to have an oil change soon. Hindi ba maarte sa oil ang engine ng yaris? I believe it shares the same engine with the vios right?

I want o put in synthetic oil. Before I was putting in Motul and RP in my alits. Can I do this on the Yaris or should I buy the Synth of Toyota? Ano ba ang viscosity ng Yaris oil? How many liters should I put in for the 1.5 engine? Thanks.