Symbiosis refers to the long-term relationship of two unlike species. Microbes symbiotically associate with plant for several reasons, most importantly, to utilize carbon compounds from the root exudates as nutrients. Most of the microsymbionts acknowledge plant provided nutrients via benefitting plant by converting atmospheric nitrogen to the plant usable form of nitrogen, solubilizing unavailable form of phosphate and zinc into available form, providing phytohormones for better plant health, and protecting plant from the pathogens and abiotic stresses. Considering the beneficial properties of plant associating microsymbionts, it could be used as biofertilizers at commercial scale. Biofertilizer is an ecofriendly solution to minimize the hazards of chemical fertilizers. Microsymbionts exert their positive impact on plant once they appropriately colonize rhizosphere or invade plant root or nodules. This review indicates that how microsymbionts colonize plant and contribute to the plant health and crop production.