Please someone can answer me how can add current Date and time and save it in database angular 8 after every single add of an element
I dont understand your question.
Is it related to flowable ? If not please note the below answer.
In type script : var date = new Data();
now you can pass this date in get or post method and get the data in spring boot or any rest controller.
After you can save this date in data base using repository.save() method.