Dear Neeran, I think you need to be made this question more clearer, so as to make necessary suggestions. In the same vein, if you need to identify bioactive compounds in your plant extract, I suggest that you used LCMS analysis.
You can use FTIR to detect some functional groups of majority compounds in extracts. Remember this technique evaluate bond interactions. So, you only will be able to suggest the possible presence of phytochemical families, not specific compounds. However, you could use some compounds (alkaloid, flavonoid, saponin,...) as patron.
Also, you could use the results to direct the chemical separation.
Dear Neeran jasim, all the previous answers are ok but if you are working with essential oils, it is possible to identify the major compounds (the minor compounds are not easily identifiable). You can read different paper from Hartwig shulz and that from our research team Hzounda et al 2016 in INDCROP. The spectrum treatment (chemometric analysis) is another stage that you should pass through. without this stage, you will not be able to have the exact peaks.