I am having the issue of connecting my voltage regulator to the trace. The trace must be thick but the pins are too small. What is the best solution? I am using proteus. Does making a solder Paste shape work? Thank you!
A trace's resistance increases with length, and decreases with thickness. So the thickness is the more important the longer the trace is.
For a very short segment of the trace, the thickness does not change the total resistance by a noticeable amount. (Connections to through-hole pads are often deliberately made thinner to increase the thermal resistance; see Does adding thermal relief on PCB increase electrical resistance?)
So the shape of the connection does not really matter. The best solution is to not worry about it.