American İPA doesn't have 3 diphthongs that ending with schwa such as ɪə,ʊə and eə while British has all of them. For example, phonetic transcription of 'here' is 'hır' in American İPA while it is 'hɪər' in British İPA but when listening American pronunciation of here , l realized that it is pronounced as if there was 'ɪə' in the American pronunciation of it.
Can anybody explain that ?
The reason seems to be historical as explained by Nardog in this answer on ELU.
However, most words that end in /r/ in General American English (GAE) usually end in a schwa in Standard Southern British English (SSBE) because SSBE is non-rhotic. 'Non-rhotic' means that only prevocalic (before a vowel) R's are pronounced in SSBE. For example, the R in real is prevocalic, so it's pronounced in British English whereas the R in hear is post-vocalic (after a vowel) and there's no following vowel, so the R in this instance is silent in SSBE. General American English (GAE) on the other hand is rhotic, meaning the R's in all positions are pronounced. So the R in both real and hear are pronounced in GAE.
Most of the time SSBE replaces the R with a schwa which in GAE would be pronounced, so better is pronounced /ˈbɛtər/1 in GAE, but /ˈbɛtə/ in SSBE.
The diphthongs /ɪə, ʊə, eə/ mostly occur before an R, and the R is silent in SSBE which gives us /ɪə, ʊə, eə/ in SSBE; however, the R is pronounced in GAE which gives us /ɪər, ʊər, eər/ in GAE (Also read the Wikipedia article on GAE diphthongs).
