The following video shows how you can add an EMA from another timeframe onto your chart in TradeStation without using any special indicators. For example, you may want to see the 8 EMA of the Daily on your Hourly chart.
IMPORTANT: If you try the approach listed and you're sure you've got everything set correctly and they're not aligning properly, check that you're loading enough data on your timeframes to complete the EMAs. For example, if you're trying to use a 50 EMA of daily data on a 30-minute chart, make sure you're loading enough data for 50 days on the daily secondary data stream. You may also want to confirm that both data streams on the same chart are aligned with the same start date using the First Date option on the Format Symbol / Settings tab.
It's also important that you set the second chart's timeframe before you add the secondary time frame. TradeStation will get confused with this approach if you start adjusting the chart's timeframe. So do not change the timeframe once you have the EMA from another timeframe added, otherwise it may stop being correctly aligned. In that case, you may need to start from the beginning to recreate the EMA again. Hint: If you do accidentally change the timeframe and it is no longer aligned with the other timeframe's EMA, you can close the workspace without saving it and reopen it to get back what you had last saved.
Some charts won't allow you to use this method, especially synthetic charts, like Renko charts. An indicator may still be needed in TradeStation if it's not possible using this technique on some of those chart types, but give it a try to see if you can get it to work, and don't be afraid to reach out to TradeStation support for assistance should you have trouble getting it to work.
For other platforms, you may need to find an indicator to accomplish the same thing. NT8 and Thinkorswim users may find the indicators referenced in this KB helpful, but use at your own risk: https://support.basecamptrading.com/hc/en-us/articles/1260804137030-How-Do-I-Add-an-EMA-from-a-Secondary-Timeframe-in-NT8-