You'll need to add your company details into the 'General' section which is located within the 'Settings' menu. here you will enter your company address and bank details. Please leave the <br/> code in after each line (see below screenshot) as this tells your mail program to neatly insert line breaks (character returns) for a much nicer looking document.
If you have more than one address this should be your main address from where you invoice etc. We ask for your bank details here so they show on invoices you send to receive. We do not use this data, it is for you and your customers use only.
In the same section you can also set the start numbers for your job sheets, quotes, invoices and purchase order numbers so they can neatly follow on for any previous software you have used until you crossed over to iManage.