Answer: Digital Design (file).
Step-by-step explanation:
Due to the variety and flexibility of digital designs, designers are able to scale up and down logos with ease to fit on business cards, posters etc.. There are many applications such as Adobe Photoshop or Illustrator that is able to design graphics and text. When saving the file, you could export it into a PNG or JPG file (more such as .tiff) however, you could save it as the respective file format e.g Adobe Photoshop -> .PSD. This allows greater control of logo designs especially when there is demand to alter or manipulate a design.
Note that it is best to design on pencil and paper to brainstorm solutions. There are also other open source or free software such as Canva or GIMP which may have less flexibility and control over the Adobe packages.