The phrase "a letter advising" is correct and usable in written English.
It can be used when referring to a letter that provides guidance, recommendations, or information about a particular matter.
Example: "I received a letter advising me on the best practices for the upcoming project."
Alternatives: "a letter informing" or "a letter recommending".
The releases will be accompanied by a letter advising the recipients that signing them is voluntary.
After he applied for a green card, he received a letter advising him that one of his forms was missing.
The V.A. says it is preparing a letter advising survivors of military sexual trauma that they can ask the department to review previously denied claims.
The MP for South West Hertfordshire, David Gauke, intervened on Williams' behalf only to be sent a letter advising the family to employ a lawyer.
Earlier this year, more than 400 dentists signed a letter advising that dental health was collapsing to "third world" levels in parts of Britain.
With half a dozen games to go, the residents of Fulham can expect a letter advising them of plans for an open-top bus parade.
In February, Notre Dame's general counsel, in a letter, advised Catholic Central to stop using the leprechaun.
In New Jersey, Archbishop John J. Myers issued a pastoral letter advising pro-choice Catholic officeholders not to seek communion.
Shortly after his consecration as bishop in 1990, he issued a pastoral letter advising Catholic abortion rights advocates to abstain from taking communion.
In a 2014 letter advising the federal government about the issue of campus sexual assault, the advocacy organization RAINN (Rape, Abuse & Incest National Network) made this point: "The crime of rape just does not fit the capabilities of such boards.
Participants receive a personalized letter advising that the questionnaire will be sent to them in the following week, and highlighting the importance of their response.
