There are multiple ways.
The first method used to preserve a shoe or tire mark impressed into soft earth is typically to photograph the mark from multiple angles. This allows investigators to document the appearance of the mark and to capture any important details or characteristics that may be relevant to the investigation. After the mark has been photographed, the next step is typically to create a cast of the mark. This is done by pouring a casting material, such as dental stone, over the mark. The casting material hardens and takes the shape of the mark, creating a detailed and accurate replica of the mark that can be examined more closely.
Alternatively, if the mark is too deep or if the casting material cannot be used, investigators may instead use a technique called lift and tape. This involves using clear tape to carefully lift the mark from the ground and transfer it to a clear backing material. The tape and backing material are then used to create a detailed record of the mark.