George Ivanovich Gurdgieff (https://en.m.wikipedia.org/wiki/George_Gurdjieff) was the first Mystic who used this word to describe an experience, in English, that happens to a person before enlightenment. And it proves the sincerity of the person on path of inner awakening.
Synchronicity happens on its own. You cannot let it happen because it is a moment when you have lost yourself as you are and experience your REALITY as it is. If you are there then REALITY cannot be.
Looking at any object in nature you become one with the object and forget yourself for that moment, that is called synchronicity with God through an object in nature.
it’s examples are looking at falling tree leaf which is carried away by the wind and the leaf offering no resistance to it- Lao Tzu got first Synchronicity with God through nature.
Looking at the last morning star in the sky Buddha got synchronicity with God through an object in nature and suddenly it disappeared too, being last morning star, so immediately he got enlightened ie synchronicity with God without any object in between.
A mystic Bulle Shah, very poor, is said to be dreaming about serving curd from his earthen pot to his guest at grand royal party at home. And suddenly the owner recognised that he is not doing the job assigned but day dreaming. So he hit him by his leg at his back. The pot Bulle Shah was carrying in dream too fell on the ground. But in that moment between dream and reality mystic Bulle shah got synchronicity with an illusionary object and at the same time without any object too and got enlightened.
It happens rarely while looking in the eyes of the other person, if it happens only when both have same thought in their mind. In that moment both feel lost of their self and see ‘the Reality’ as flashing of light that is beyond both. That is synchronicity with a person-as described by Osho through his own experience with Babu Shambudayal, An advocate-as described in his book ‘golden childhood’.
In the process of enlightenment synchronicity is a must step.
Enlightenment is synchronicity with God without any object in between