Text representation, in simple words, is representing text in sensible numeric form. You can read in detail from the following paragraph
Text representation is one of the fundamental problems in text mining and Information Retrieval (IR). It aims to numerically represent the unstructured text documents to make them mathematically computable. For a given set of text documents $D = \{d_i, i=1, 2,...,n\}$, where each $d_i$ stands for a document, the problem of text representation is to represent each $d_i$ of $D$ as a point $s_i$ in a numerical space $S$, where the distance/similarity between each pair of points in space $S$ is well defined.
But, I came across the phrase "text feature representation" in research papers. Features, in general, are present in dataset. But, I think, features can be characters or words or documents or complete text (as a single feature?) in the case of the text. I am not sure about what we call features in the text.
So, I am not sure about what is meant by text feature representation. Is it the same as text representation?