Doctor Who Magazine (in-universe)

Doctor Who Magazine, also abbreviated to DWM, was a publication that celebrated the Doctor Who series. The publication also had a comic strip by 2016. (PROSE: A Letter from the Doctor)

History
On 29 April, 2016, Peter Capaldi was requested to write a letter for the five-hundredth issue, as well as either the one-thousandth or one hundred-thousandth issue, but the actor couldn't remember which.

In his letter, he wrote about how he was proud about the magazine and how it inspired fans to "write their own stories, draw their own pictures, and make their own music and films". (PROSE: A Letter from the Doctor)

On 10 May 2020, a desktop icon was seen on Petronella Osgood's laptop. (WC: The Zygon Isolation)

Alternate universes
There also existed a Doctor Who Magazine in a universe where the Doctor was entirely fictional. (PROSE: The Thief of Sherwood)

Behind the scenes
This is clearly a reference to the real world magazine, referencing logos used in the 90s (note that color might change with each issue, so while the particular colors shown here might not be present in one version of the logo, that doesn't preclude them from being present in another).