PhD is an academic degree awarded by universities. Universities confer this on people who have completed a course of study in their chosen field that has been deemed to be rigorous enough for advanced work， and which satisfies the educational standards necessary so students can continue with scholarly pursuits. In some countries， PhD degrees are given without any examination or dissertation but require a thesis paper (in American academia). In most other places， there’s no need for a written thesis paper - it's just like you get your master's， then move onto doctorate level courses only after all coursework is finished if you want to pursue academics further... A Master‘s/Master's equivalent is required for pursuing professional fields(lawyers，engineers，practitioners etc)， where as Doctorate is not usually needed except perhaps medicine and dentistry…
For doctoral studies， admission requirements include completion of previous programs at university-level (e.g. bachelor's and/or master's）；a portfolio showcasing the applicant's prior scholarship（research projects undertaken during past degree studies or postgrad research activities）and writing skills；professional experience may also be considered…… The application process typically includes submission of transcripts from previously attended institutions（i.e. grades earned along the way）， recommendation letters， statements of purpose， samples of writings submitted by the applicants e.g. papers presented at conferences， interviews conducted on campus by faculty and graduate representatives等……
The U.S. education system doesn't operate using English language tests as such， because we already use IELTS/TOEFL scores to assess proficiency in reading and listening，etc. We do however accept the TOEFL PBT test score as well as Cambridge English Test and Pearson Test（PTE Academic）with respect to our postgraduate programmes…
