Yes. You must separately state the sales tax amount on your invoice or receipt unless you provide a written statement to the customer that the sales price includes sales tax. The “tax included” statement must be displayed where people normally are advised of the terms of the sale.
If you include the sales tax in the sales price, you have collected sales tax and must report the collected tax by backing it out of total amount received from the customer.
For example, you sell office supplies. You are in El Paso and are required to collect 8.25% tax on your sales. If your price was $50 and your invoice states that the sales tax was included in the total then you would report taxable sales of $46.19 and sales tax collected of $3.81. You can check your figure by multiplying the computed sales amount ($46.19) by the sales tax rate (8.25%) to ensure that it equals the calculated sales tax amount of $3.81. Don’t forget the total of the computed sale and the computed tax need to add up the $50 collected.
Like any good CPA, I need to add a disclaimer: Unfortunately, it is impossible to offer comprehensive tax info over the internet, no matter how well researched or written. And remember, I love my readers but having me bookmarked on your computer doesn’t make you a client: before relying on any information given on this site, contact a tax professional to discuss your particular situation.