1. Go to Settings, Customization.
2. Customize Entities and Choose the Account Form.
3. Choose Forms and Views, Form, and Form Properties.
4. On the Events tab, make sure that OnLoad is highlighted, then click Edit.
5. Paste the following code and make sure that the box for Event is Enabled is checked:
//resize window to full screen upon opening Account forms
6. Save and close the form and publish the entity.