You can pan to reposition a view and zoom to change the magnification of a view.
Typically, you pan and zoom the current view with a wheel mouse or similar device. Rolling the wheel zooms the view, while pressing and dragging the wheel pans the view.
In the Model tab example below on the left, the current view is the entire drawing area. The example on the right displays two model space viewports, one of which is highlighted as the current viewport. You can click within a viewport to make it the current one, and you can then pan and zoom the view displayed in it.
In the layout tab example below on the left, the current layout viewport is highlighted, in which you can pan and zoom an area of model space. In the example on the right, double-clicking outside the layout viewports puts you in paper space, where you can pan and zoom the entire layout. This is how you would magnify the area of the title block.
In addition to zooming with the mouse wheel, commonly used options of the ZOOM command include the following: