please post your used code correctly – see https://codex.wordpress.org/Forum_Welcome#Posting_Code
seems that by default, and via the style.css of the theme, the ‘decimal’ style is set.
using the ‘text’ setting of the editor, you could add a style to the ol tag; example:
<ol style="list-style-type: lower-roman;">
<li>line one</li>
<li>line 2</li>
<li>line 3</li>
</ol>
Another approach — put this in the child theme’s style.css or in the Appearance / Edit CSS window.
ol.lower-alpha {
list-syle-type: lower-alpha;
{
ol.lower-roman {
list-style-type: lower-roman;
{
Then in you pages when you want to use lower alpha, use the class you want for the ol.
<ol class="lower-alpha">
<li>item</li>
<li>item</li>
<li>item</li>
</ol>
<ol class="lower-roman">
<li>item</li>
<li>item</li>
<li>item</li>
</ol>
Correction to the CSS–change each last opening curly bracket to a closing curly bracket! Duh!
ol.lower-alpha {
list-syle-type: lower-alpha;
}
ol.lower-roman {
list-style-type: lower-roman;
}