Look in your owners manual for the correct type and weight. Usually it is 30W straight, but some manufacturers are using 10W-30. Use a quality oil as you will not need much of it to completely change the oil. I have always avoided Quaker State and Pennsoil, as they tend to leave sludge in the engine. Havoline, or one of the Mobile type oils are OK, but don't waste your money on synthetic oils as you are going to change your oil several times during the mowing season.
If it isn't written in the manual or if you don't have the manual then call the manufacturer or look up the model on the manufacturer site. Probably most mowers take just about the same thing but you gotta be careful because sometimes there may be an oddball out there that needs something really specific.
the regular 10w30 be fine,,, no need to waste money on Mobil 1 in a lawn mower
I always use Mazola corn oil....it's healthier and low in cholesterol...lol
The brand they specify