The "stock" MFD's, and some add-on MFD's use the menu-driven target selector, operated with the direction keys as outlined above.
Some add-on MFD's such as BaseSyncMFD and AerobrakeMFD use a "dialog box". For these, you must type in the name of the target. Spelling matters, you can use "Object Info" (accessible from the <F4> menu, or IIRC by pressing <Ctrl><I>) to check an obect's spelling. The "dialog box" is not "case-sensitive", so capitalization isn't important.
Some MFD's, most notably DockMFD and VTOLMFD, can simulate the use of radio transmitters, and will only target objects close enough to be "in-range" of the transmitter. The vessels receiver's must be set to the correct frequency also, by using COM/NAV MFD. VOR transmitters have a much longer range than IDS or ILS transmitters.
They can be used during the later stages of Orbital Syncronization or initial approach to a base. Once closer, the IDS/ILS frequencies can be used to target indivual docks/pads.
BTW, DockMFD can be manually targeted to docks close by, but without IDS transmitters, by using the <vis> button, or manually to any dock with the <TGT> button without having to set an IDS frequency.