That depends on what you are applying it to, and in some cases, the thermal paste. Many pastes will come with application instructions, follow them.
Naked die GPUs and Laptop CPUs, cover it. Can't really have too much.
CPUs consumer Intel, a bead the width of the applicator nozzle in the same direction of the CPU die. This is most commonly 'vertical' with LGA 115x and 1200 in a standard desktop, on LGA 1700 it is lengthwise with the longer rectangle side.
Consumer AMD has 2-3 dies under the heat spreader. Common recommendation is five small dots. One in the center and one in each corner halfway between the center and the actual corner of the CPU.
Larger CPUs like Intel HEDT and AMD Threadripper. Large X shapes and small blobs...