Mass of long distance starts? how it be measured

How do we measure the distance and mass of the long distance placed star?

The distance to the nearest stars is measured by triangulation. Astronomers observe the star's position relative to even more distant background stars at one point in the Earth's orbit and then repeat the measurement 6 months later. The apparent shift in the star's position can then be used to calculate its distance.
The mass of a star is easy to compute from Newton's law of gravitation if it has a smaller companion that orbits it. Many such stars do. From studying such pairs, one can make generalizations about the relationship between a star's mass and its brightness and color. One can then apply these generalizations to estimate the mass of stars that do not have companions.

We don't measure it, we estimate it. (it's not a guess)

We compare it to the sun, if it is brighter than the sun it must be more massive.