Generally, your contact info should be on the opposite side of the recipient's info. So if your business name and logo are on the right side of the invoice at the top, the client's name and info should be below this on the left side.
Sales Tax: Depending on your jurisdiction and type of business, the tax requirement can get complicated. Be sure to follow instructions from your local tax bureau and include the appropriate tax amount on the invoice. Pro tip: Use an invoicing software to manage your business activities, change tax settings as you want and make your tax time easier.