For your convenience, Argenta allows you to create a bulk texting list and then allows you to send out bulk text messages to that list.
First, you must create a Text List. A text list is a list of constituents created for the purpose of mass text messaging. 
Create A Mail List from A Relationship Screen (eg: Donors)
Relationship management screens like Donors have a "Filter List " function that allows the list to be narrowed down by selecting specific criteria and filtering the list.
After you filter the list you can use the "Choose a Bulk Action for Selected Records" to select all records and add them to the text list. Simply choose the  "Add List to Mail Room" button above the list to create a text list from your results.
This will open the Add A New Mail List window.
Steps to creating a list:
1. Place a check mark in the "Text List" box and give your list a title in the "Mail List Title" box.
2. You can restrict access to the list by assigning a Department/Chapter, District, or Precinct.
3. Once you are ready to create the list click the "Add This List" button. Your list will be added to the mail room under Text Lists.
Once you have a Text List created, you are ready to do a bulk text message.  
To get started, select Argenta Mail Room, from the main menu on the left side of the screen.
This will take you into your Mailing, Email and Text lists. From here, choose the "My Text Lists" tab.
This will open the Mail Room - SMS Text Messaging Lists screen. From here choose your list by selecting the "Select A Text List To Display" drop-down and selecting your list from the menu.
This will bring up your list for you to send the bulk text message too. This is where you can look through the list one more time and make any changes if needed by deleting a constituent or adding a constituent to the list.
To delete a constituent from the list, simply click the delete icon  behind the corresponding constituent you wish to delete.  
To add a constituent to the list, click the "Add Constituents" button. This will open a search box for you to type the name of the constituent into, then click the "Search" button. Your constituents that match your search criteria will be listed. To add a constituent click the corresponding add icon for the constituent you wish to add.
Once your are ready to send a bulk text to your list, click the "Send A Text to List" button.  
This will open the Send Bulk Texts screen.
Simply type in the text message that you wish to bulk send to these constituents and click the "Send Text" button.
Your bulk text message has been sent to all recipients.  
Unfortunately, there is no way for us to know if a text message did not get delivered. This could be due to a wrong number or a phone number no longer being in service. Again, there is no way to confirm delivery or receipt of the text message.
*Terms of Service for using Text Messaging:
You guarantee that you are aware that, among other requirements, the TCPA and CTIA rules require prior express written consent from a consumer before you can send them marketing text messages and such consent must be unambiguous (i.e. the consumer must receive a clear and conspicuous legal disclosure). Furthermore, damages for each message sent in violation of the TCPA is $500 and can be $1500 if the violation is proven to be “willful and knowing.” If for any reason Devscape Software suspects that your constituents received text messages contrary to any governing rules, it reserves the right to request a written explanation from you, the client, including the method of collecting the constituent’s phone numbers and a guarantee signed by you that all the people on your subscriber list agreed to receive text messages from you of the type that you had sent. Devscape Software reserves the right to take any action it thinks appropriate in the case of non-compliance, including but not limited to cancellation of your account.