N-Methyladenosine (mA) is the most widespread internal messenger RNA modification in humans. Despite recent progress in understanding the biological roles of mA, the inability to install mA site specifically in individual transcripts has hampered efforts to elucidate causal relationships between the presence of a specific mA and phenotypic outcomes. In the present study, we demonstrate that nucleus-localized dCas13 fusions with a truncated METTL3 methyltransferase domain and cytoplasm-localized fusions with a modified METTL3:METTL14 methyltransferase complex can direct site-specific mA incorporation in distinct cellular compartments, with the former fusion protein having particularly low off-target activity. Independent cellular assays across multiple sites confirm that this targeted RNA methylation (TRM) system mediates efficient mA installation in endogenous RNA transcripts with high specificity. Finally, we show that TRM can induce mA-mediated changes to transcript abundance and alternative splicing. These findings establish TRM as a tool for targeted epitranscriptome engineering that can reveal the effect of individual mA modifications and dissect their functional roles.