Hi Jayesh,

Positive flux means flux is leaving the hose; the hose is a source of flux. Negative flux is like water entering a sink; it is a sink of flux. So positive flux = leaving.

OR

Field lines directed into a closed surface are considered negative; those directed out of a closed surface are positive.

The negative flux just equals in magnitude the positive flux, so that the net, or total, electric flux is zero.

Hope this will help,please feel free to ask if you have any further queries.

Thank You.

Hello

Electric flux linked with a surface is positive if the electric field lines are flowing outwards of the closed surface while it is negative if electric field lines are moving inwards also the net charge is contained inside a closed surface,

Also the total flux through the surface is proportional to the enclosed charge,
so it positive if the net charge inside the surface is positive
and  negative if the net charge inside the surface is negative.

Thankyou