Start date in Cloud Edition

I am facing a problem when setting the opening balances, especially for suppliers and customers, and when reviewing the topics, I found that the start date must be chosen, but I do not find this option in the program properties. Is there a way to put the transactions with the customer or supplier that took place before the start of the financial period

How did you go with the approach described in the guides, specifically:

Starting Balances: Enter starting balances | Fix starting balances

There are also more specialized Guides on starting balances for customers and suppliers.

For the record, start date is not a setting. It is just the date you start using Manager b

Manager is a perpetual accounting application. As long as you did not set a lock date you can enter anything at any date in history. As @Tut says therefore there is no need for a start date as it would be the date of the earliest entry you make.

I want to close the current period and start a fresh one with same inventory items &clients profiles is there any way to import all (inventory items & client’s profiles) or I must add it again one by one

That is not how Manager works. As @eko said it is a perpetual system. See the Guide: Close an accounting period | Manager.