Usually, It is a fast process that takes place in a matter of seconds, nevertheless, the payment method that you have chosen, requirements from the seller mentioned in the terms, or the time taken by the seller to release your Bitcoins can change a little bit this. Therefore, you have to choose wisely what type of payment method you are going to use because it can be faster or slower than others, perhaps If you do a bank transfer or a cash deposit you will realize that those two options are faster than others.
On the other hand, there is not a fixed time for doing a deposit or withdraw, yet the higher you pay for your transaction fees the faster the transaction will be, this is the case for cryptocurrencies deposits to Overblock platform, transactions take some few minutes to an hour as an average time. Transactions within the platform are immediate.
If you want to make a withdraw it is going to take less than an hour and it also depends on your final wallet