1. A method of identifying one or more fillable fields of an electronic form, the system comprising: receiving, by an electronic device, an electronic form, wherein the electronic form comprises an image of a document; identifying, by an electronic device, one or more fillable field candidates of the electronic form; determining, for each fillable field candidate, whether the fillable field candidate is a fillable field by: identifying one or more box candidates from the fillable field candidates, and for one or more of the box candidates: generating an out-border for the box candidate, wherein the out-border is a rectangular zone that surrounds an outer portion of the box candidate, generating an in-border for the box candidate, wherein the in-border is a rectangular zone that encompasses at least a portion of the box candidate, determining a histogram of pixels of the box candidate between the in-border and the out-border, determining a ratio of black pixels to white pixels of the histogram, and in response to the ratio exceeding a threshold value, determining that the box candidate is a fillable field, otherwise, determining that the box candidate is not a fillable field; and updating metadata associated with the electronic form by applying, by the electronic device, a sequencing framework to only the fillable fields by: obtaining position information for each fillable field, wherein the position information indicates a position of the fillable field on the document as displayed via a display device, sorting the fillable fields based on the position information to form a sequence of fillable fields, determining a designator to each fillable field, wherein the designator indicates a position of a corresponding fillable field in the sequence, and storing the designator in a data store such that it is associated with the corresponding fillable field.
5. The method of claim 1 , wherein determining whether the fillable field candidate is a fillable field comprises determining whether the fillable field candidate is a line by: obtaining dimensions for the fillable field candidate, wherein the dimensions includes a height value and a length value; and in response to the length value not exceeding a first threshold value and the height value exceeding a second threshold value, identifying the fillable field candidate as a fillable field.