anyhow when taking portrait specially outside the background should be blurred (DoF?)
Although people talk like there are, there are no rules in photography. There is no one correct way to take a photograph of a person. The subject doesn't have to be in focus. The subject doesn't have to be properly exposed. The composition does not have to adhere to the rule of thirds, and the horizon does not have to be straight.
HOWEVER if you want to make attractive, flattering photos of people, there is a fair bit of accumulated knowledge of how this can be done.
I suggest looking up famous portrait photographs, finding ones you like, then looking up the work of that photographer. Look at photographs you like a lot, and try to work out what has been done ie expression, lighting and composition.
oki ill make it easy for myself about the aperture let say the lowest number (1.8) the wider the "IRIS" is and the background will be blurry, the highest number (22) the "IRIS" will become small and the background/whole scene will be in focus.
What aperture to choose? Say, for example, you have a 50mm f/1.8 lens and an APS-C camera, say a canon 550D. If you want to isolate the subject sharp against a blurred background, a large aperture would be necessary. But at f/1.8, the lens is not particularly sharp, to get very high IQ at least f/2.8 is needed. On the other hand, the IQ at f/1.8 may be perfectly good for you, you have to take a lot of photos, and examine them critically, and work out for yourself what you like. With that same camera and lens above, if you wanted to have everything in focus from foreground to background, f8 or f11 would be appropriate. From f13 to f22 IQ declines fairly rapidly due to diffraction. Sometimes this is desirable in a shot where the context is important, eg most journalism, environmental portraiture etc. Look up famous portrait photos, and count how many were done with very shallow DOF. What is it that makes them great?
when cropping will you just use the crop tool and just crop the desired size or image that need to be cropped?
Try to shoot so you don't have to crop. Get closer, frame tighter.
--
All matter is energy condensed to a slower vibration,
And we are all one consciousness experiencing itself subjectively.
Death is an illusion,
Life is a dream,
And we are the imagination of ourselves.