On the client's card, just click the pencil icon and you can edit, add, or remove information and then save the changes.
If you want to change a piece of information for several contacts at once — and it's the same for those contacts — you can use the Changes function.
First, select the contacts you want in the database (the empty square). Then, click the button with three horizontal lines and choose the Changes field.
Select the parameter you want to change and enter its new value.
After saving, the original value for the selected contacts will be changed to the newly chosen value.
