This index card appears to have come from The Veterans Administration Master Index (NAID: 76193916), which has been published as United States, Veterans Administration Master Index, 1917-1940 (digital images) at FamilySearch, and as an index-only database at Ancestry as U.S., Veterans Administration Master Index, 1917-1940. These records were created by the Veterans Administration and are part of Record Group RG 15, Records of the Department of Veterans Affairs, 1773 - 2007.
NARA's catalog description says:
Function and Use: The Veterans Bureau (and later the Veterans Administration) created the card index for each veteran who had insurance applications, conversions, veterans who had filed claims with their agency, and veterans who were paid a WWI bonus.
The catalog description page at FamilySearch for the collection has a Learn More link which takes you to the corresponding article United States, Veterans Administration Master Index (FamilySearch Historical Records) in the FamilySearch Research Wiki.
The article lists the following codes:
- K - Life Insurance
- A - Adjusted Compensation (Bonus)
- T - War Risk Insurance
- R - Rehabilitation
- CT -WWI Certificate
- I -Permanent Disability
For more on the codes, see the "Key to Codes and Prefixes" handout created by NARA's National Personnel Records Center (link at the bottom of the answer).
Scope and Content
NARA's Scope and Content note in the catalog description says:
This series consists of microfilmed cards bearing the name of the veteran and may include personal identifying information including home address at the time of enlistment, date of birth, and date of death. Additionally, the cards may provide the following service information: rank, branch of service, service number, date of entry and discharge, claim number, insurance number(s), cross-reference to the beneficiary of the veteran, and first organization the veteran was assigned.
Citing your sources
One of the five elements of the Genealogical Proof Standard is to write complete source citations for all the records we find. This helps us keep track of where we found them, but more importantly, it allows us to preserve the context -- who created the record and for what purpose, when and where the record was created, and how the record was created. All of these things help us interpret the information contained in the record.
The catalog record at FamilySearch says:
To view digital images of
this United States, Veterans Administration Master Index, click here.
Not available on microfilm.
This is a preliminary description provided to allow immediate online
access. Images have not been reviewed.
Digital images of originals held by the National Archives and Records
Administration, St. Louis, Missouri.
Knowing whether a database has been published from digital originals vs. a microfilm publication, and knowing where the originals are held gives us clues about where we can find more information. NARA microfilm publications sometimes have a DP (descriptive pamphlet) at the beginning of a microfilm roll, or as a download via the microfilm catalog.