The subjunctive form of the verb expresses hypothetical situations, request, suggestion, administrative order, contra factual statement and obligation. They are generally used in relative and conditional clauses.  Subjunctive clauses as subordinate clauses are generally used at the end of the main clause.

Functions: prescriptive function (खुद को जय करें) and descriptive function (मैंने उसे सुझाव दिया कि रोज़ व्यायाम करें)

Use: in, in relative clauses and conditional clauses.

• कि-subordinate clauses: वह चाहती है कि मैं उसे हिंदी बोलना सीखा दूँ। 
• relative clauses: जो हिंदी पसंद करता हो उसे यह लेख पढ़ना चाहिए।
• in conditional clauses — express two meaning: non contra factual; contra factual for hypothetical situations (अगर मैं रईस होता…)

Subjunctive forms are: 

• non-aspectual (simple subjunctive verb): formed by deleting the final suffix (गा/गे/गी) from the future form of a simple verb (करेगा>करें; करोगी>करो; होंगे>हों )
• aspectual (complex subjunctive verbs: formed by changing the final verb in an indicative verb form to a non aspectual subjunctive verb (कर रहा है>कर रहा हो)

_{Note: Native speakers of Hindi also use हम करूँगा, हम हूँ  (especially in the Bihari regional dialects) as subjunctive forms. It is different from standard Hindi form but is not considered incorrect.}