Please how can i merge two track using audicity?
Not a lot of info there.
Import both sound files into audacity. They will appear one above the other and play at the same time. Drag-Select the bottom one, copy and paste it on the end of the top one.
Define what you mean by “merge”. Do you want them to play one after the other? Then follow Koz’s advice. Do you want them to be blended together (we call that “mixing”)? In which case you can use the Gain sliders (labelled with a + and a -) in the panel at the left of each track to set a general level. When you do File > Export, Audacity will create a stereo mix of the two (or more tracks). If you want more control over the mix you will need to use the Envelope tool instead of, or as well as, the Gain control.