In this Internet Era, Email is a vital form of communication for many academic, personal, and professional users. Despite the availability of alternative means of communication, such as social networks, electronic messages, and mobile apps, email remains an integral part of communication. Email auto-management techniques are necessary for a variety of reasons, such as saving users valuable time, dealing with high-dimensional data, and making email communication easier and more accessible. In this work, a novel email net (improved elephant herd optimization and Graph similarity with the Jaccard index) technique has been proposed for efficient email classification based on graph similarity measure. Initially, the dataset is pre-processed using NLP techniques such as removing email signatures, removing punctuations, removing stop-words, lowercase conversion, tokenization, and stemming for removing irrelevant data. After pre-processing the feature are extracted using bag of words and term frequencyinverse document frequency (TF-IDF). These extracted features are given as input to improved Elephant herding optimization (EHO) for selecting the most relevant features to build a graph-based similarity index for classifying each category of e-mail. The proposed email net was tested on a benchmark dataset and a real-time dataset. Also, the proposed method's performance is compared with other classifiers. According to the experimental results, the proposed approach outperforms all other classifiers with a 98.82% of accuracy.