It was recommended that the international development partners develop guidelines or a roadmap to help countries take the necessary steps to select the right tool for their purposes.
Why is it using present tense “develop” in the sentence which is actually a past tense “It was recommended”?
This is not a present-tense form but an instance of what traditional grammar called the mandative subjunctive, one of the last surviving remnants of the subjunctive in English. In subordinate clauses expressing the substance of a command or suggestion or recommendation, the tensed verb employs the bare infinitive form: the infinitive without to.
They recommended that partners develop guidelines.
She suggests that he dedicate more resources to R&D.
We order that you be hanged by the neck until you are dead.
Today these subordinate clauses more commonly use should, but the “subjunctive” form is by no means rare, particularly in the most formal contexts.
The tense on the verb in your subordinate clause here does not match that on the verb in the main clause because the two clauses occupy different times and modalities. The recommendation is something which has actually happened, but the development is something which lies in the future and may not happen at all.