Add an input field where you can enter any text:
Manipulate[
Graphics[
Table[Rotate[
Rotate[Translate[
Text[Style[text, s, FontFamily -> "Times"]], {d, 0}],
a \[Degree]], i 72 \[Degree], {0, 0}], {i, 1, 5}],
PlotRange -> 2],
{{d, 1, "distance"}, -2, 2},
{{a, 0, "rotation"}, 0, 360},
{{s, 200, "size"}, 0, 400},
{{text, "a", "text"}}
]
With that kind of input field, you have to put quotes around what you type to indicate that it’s text (and not a symbol). Make the input field automatically treat what you type as text so you don’t need to type the quotes:
Manipulate[
Graphics[
Table[Rotate[
Rotate[Translate[
Text[Style[text, s, FontFamily -> "Times"]], {d, 0}],
a \[Degree]], i 72 \[Degree], {0, 0}], {i, 1, 5}],
PlotRange -> 2],
{{d, 1, "distance"}, -2, 2},
{{a, 0, "rotation"}, 0, 360},
{{s, 200, "size"}, 0, 400},
{{text, "a", "text"}, InputField[#, String] &}
]
Manipulate[
Graphics[
Table[Rotate[
Rotate[Translate[
Text[Style[text, s, FontFamily -> "Times"]], {d, 0}],
a \[Degree]], i 72 \[Degree], {0, 0}], {i, 1, 5}],
PlotRange -> 2],
{{d, 1, "distance"}, -2, 2},
{{a, 0, "rotation"}, 0, 360},
{{s, 200, "size"}, 0, 400},
{{text, "a", "text"}, InputField[#, String] &}
]